Charging device for concrete mixers



April 15 1924.

E. H. LICHTENBERG CHARGING DEVICE FOR CONCRETE MIXER Filed June 21, 1922Inventor E. Ii Liclz ienbezg I v 5 3 I 1 Wizneam- 13 I I r I M Mun-113$Patented l5, i924.

ca rn r ERICH H. LIGHTENBERG, 0F MILW'AUKEE, WISCONSIN, ASSIGNOR TOKOEHRING- COM- PANY, O'F MILWAUKEE, WISCONSIN, A CORPORATION. V

CHARGING DEVICE FOR CONCRETE MIXERS.

Original application filed June 17, 1920, Serial No. 389,632. Dividedand this application filed June 21, 1922. Serial No. 569,855.

To all whom 2'25 may concern.-

Be it known that I, Enron H. LICHTEN BERG, a citizen of the UnitedStates, residing at Milwaukee, in the county of Milwaukee and State ofVVisccnsin, have in vented certain new and useful Improvements inCharging Devices for Concrete Mixers, of which the following is aspecification.

The present invention relates to certain new and useful improvements incharging devices for concrete mixers of that general type which isillustrated by Patent No. 1,107,171 which was granted on August 11, 1914to P; A. Koehring.

Among the objects of the invention is to provide a power driven chargingdevice embodying novel means whereby the loading skip or hopper isstarted into motion with a slow speed so that there is a minimum amountof strain on the mechanism and the power is utilized in the mostadvantageous manner to overcome the initial inertia of the load. Afterthe loading skip or hopper has been started into: motion there is agradual acceleration of the speed thereof and then an automaticretarding of the speed as the loading skip or hopper approaches thelimit of its movement where it discharges into the mixerf In other wordsthe loading skip or hopper acquires its maximum speed at an intermediatepoint in its path of movement and the speed is gradually accelerateduntil thi maximum speed is reached and then gradually retarded as theloading skip reaches either limit of its movement. Such a constructionreduces to a minimum the strain and shocks on the mechanism and enablesthe power to be utilized in the most advantageous and economical manner.

The subject matter for this application has been divided out of aco-pending application for a loading device which was filed by me onJune 17, 1920 and is identified by Serial No. 889,632 patented June 26,1923, Patent No. 1, l59,779.

For illustrative purposes one particular embodiment of my invention hasbeen illus trated and will be described in detail, al though it will beunderstood that many modifications and changes can be made in thedetails of construction without departing in any manner from the spiritof the invention.

For a full understanding of the invention reference is to be had to thefollowing description and accompanying drawing on which the figure isarear elevation of a power driven concrete mixer, provided with acharging device constructed in accordance with the invention.

Throughout the following description corresponding and like parts arereferred to by like reference characters, and the same referencecharacters are used on the draw- 111g.

Referring to the drawing, the reference character A designates theskeleton supporting frame of a portable concrete mixer, said frame beingmounted upon a truck B so that it can be readily moved from place toplace. A conventional concrete mixer C is mounted. upon the frame A, andan engine D is provided for driving the mixer and other mechanismsmounted upon the frame and associated therewith. A loading skip E of awell known type is provided for charging the material andaggregates'into the drum of the mixer. This loading skip is pivotallymounted at 1 upon the frame A, and is adapted to swing up and down. Whenthe loading skip is in a lowered position it rests upon the ground orroad and the materials to be mixed are dumped or de posited therein.When the loading skip is swung upwardly and reaches the limit of itsupward movement, the materials which were previously deposited thereinare discharged by gravity into the drum of the mixer. A somewhat similarmechanism is disclosed in the Koehring Patent No. 1,101171, which wasissued on August 11, 1914, and in view of the disclosure of this patenta further description of the mixer and specific construction of theloading skip is not thought to be necessary.

Extending transversely across the bottom of the loading skip E is across bar 2, and an intermediate portion of a cable 3 extendslongitudinally of the cross bar and slidably engages the same. From theopposite ends of the cross bar the cable is carried upwardly andpassesaround guide pulleys l which are suitably journaled upon the frameA. Afterextending around these pulleys the ends of the cable are carrieddownwardly and suitably anchored or secured to winding drums 5 on a skipoperating shaft 6. This shaft is operatively connected tothe engine D inany suitable and conventional manner, such as that dis closed by theabove identified Koehring patent. The shaft is shown as provided with alarge drum 7, and this drum may have a cable connection with mechanismoperatively driven by the engine D. This is a form of connection whichis well known in the art and no claim to novelty is based thereon inthis application.

The winding drums 5 have a peculiar formation which is essential tocarry out the idea of the present invention. Each of these drums isprovided with a helical groove 5 which causes the cable to be woundthereon in a predetermined manner, and the drum is tapered towardopposite ends thereof. With this construction it will be obvious thatwhen the skip operating shaft 6 is driven at certain speed, the windingor unwinding action of the drums 5 with respect to the cable 3 will bemuch more rapid at the intermediate larger portion of the drums than atthe tapered or reduced end portions thereof. The loading skip thusacquires its maximum speed at an intermediate point in its path ofmovement, the speed being gradually accelerated from the time theloading skip is started into movement until the maximum speed isacquired, and then being gradually retarded until the loading skipreaches the limit of its movement.

When the loading skip is in a lowered position the materials for thenext batch of concrete to be mixed in the drum are placed therein, andwhen it is desired to charge these materials into the drum, power isapplied to the skip operating shaft 6 from the engine. This causes thecable ends 3 to be wound upon the drums 5, and the initial winding is attapered or reduced ends of the drums, with the result that a minimum ofspeed and a maximum of power is available for overcoming the initialinertia of the loaded skip and starting the same into motion. After theskip has started on its upward movement the speed thereof is graduallyacceleated, until the maximum speed is acquired at an intermediate pointin the path of movement of the skip. The speed of movement of the skipis then gradually retarded as the cable ends approach the other reducedends of the winding drums, the skip being brought to a stop when itreaches its upper limit of movement, at which position the contentsthereof are discharged by gravity into the drum of the mixer. The poweris thus utilized in the most effective manner for moving the loadingskip and at the same time the charging operation iscompleted as quicklyas possible and without any unnecessary loss of time, it beingunderstood that time is always an important element in the operation ofmachines of this character.

It may be mentioned that the lifting crane F which is shown at the righthand side of the figure in the drawing is adapted to be utilized forswinging batch boxes over the loading skip for the purpose ofdischarging the contents of the batch boxes into the skip when thelatter is in its lowered position. This loading crane is also operatedfrom the engine D, and the mast 8 thereof is slidably mounted so thatthe foot 9 at the bottom thereof is normally held above the surface ofthe ground by the action of a spring 10. This loading crane is fullydescribed and claimed in my copending application, Serial No. 389,632,filed June 17, 1920, of which this is a divisional application, andreference is made to the parent case for complete disclosure of theconstruction and manner of operation of this crane attachment.

It will be obvious, of course, that the winding drums 5 may be taperedonly in one direction if the invention is used under conditions where itis not desired to retard the speed of the loading skip as it reaches theupper limit of its movement. The single taper would cause the loadingskip to be started at a slow speed and the movements thereof graduallyaccelerated until the maximum speed was reached. Also, the shaft 6 mayor may not be driven at a substantially constant speed, depending uponthe particular mechanism with which the invention is used. The cableconnected to the large drum 7 on the shaft 6 might, of course, cooperatewith a tapered drum on the lower shaft, so that the shaft 6 itself wouldhave a variable and accelerated speed. In all of these constructions,however, the essential idea of the device would be retained, namely,that of starting the loaded skip at a slow speed and then acceleratingthe speed thereof until the maximum speed is reached.

Having thus described my invention what I claim as new and desire tosecure by Letters Patent is,

In a machine of the class described, in combination, a portable supportfor concrete mixers or the like, a loading skip pivoted at one end tosaid support to move from a position substantially horizontal andresting upon the ground to a position in which it is elevated so as toassume an almost vertical adjustment for discharging its contents, anoperating means for raising said skip from its lower position to its hiher position, comprising cable drum mec anism including drums mounted onthe upper portion of the support somewhat adjacent to the point ofhigher adjustment of the skip when discharging, each of said drumsembodying a cable winding surface, the intermediate portion of which isenlarged and the opposite ends of which are of reduced diameter, cablesadapted to Wind about said drums and connected with the skip and meansto operate the cables to cause Winding of the same on the drums to movethe skip from its lower position to its higher position, the formationof the Winding surfaces of the drums being such that the cables areWound on the reduced ends of the drums at initial slow speed until theskip is raised to the plane above the pivotal axis thereof, whereuponthe movement of the

